N-terminal proteolytic processing of porcine chromogranin A in parathyroid tissue
| Autor: | Sven Ulrik Gorr, Brigitte H. Fasciotto, David V. Cohn |
|---|---|
| Rok vydání: | 2002 |
| Předmět: |
endocrine system
Sucrose Swine Physiology Sequence analysis Acid Phosphatase Immunoblotting Molecular Sequence Data Clinical Biochemistry In Vitro Techniques Biology Cytoplasmic Granules Biochemistry Parathyroid Glands Cellular and Molecular Neuroscience chemistry.chemical_compound Endocrinology Sequence Analysis Protein Chromogranins Animals Endocrine system Amino Acid Sequence Protein Precursors Peptide sequence chemistry.chemical_classification L-Lactate Dehydrogenase Edman degradation Chromogranin A Parathyroid chief cell Peptide Fragments chemistry biology.protein Glycoprotein Protein Processing Post-Translational |
| Zdroj: | Regulatory Peptides. 103:53-58 |
| ISSN: | 0167-0115 |
| DOI: | 10.1016/s0167-0115(01)00328-7 |
| Popis: | Chromogranin A (CgA) is a glycoprotein stored in secretory granules of many endocrine and neuroendocrine cells. CgA undergoes tissue specific processing to release regulatory peptides. In the parathyroid, although processing is limited and variable, several CgA-derived peptides have been characterized including parastatin and betagranin. An early stage of CgA processing is the generation of a 64-kDa fragment (CgA64). In this study, we have purified CgA64 from porcine parathyroid glands by chromatographic separations. Edman degradation of this CgA64 yielded the N-terminal sequence NDQAELKEGTEEASSKEAAEKRGDXAVEKND corresponding to pCgA(94-125). Amino acid composition suggests that CgA64 corresponds to CgA(94-430) (i.e. the entire CgA molecule, less the N-terminal residues 1-93). To determine the origin of CgA64, we fractionated parathyroid membrane vesicles by sucrose gradient centrifugation. Intact CgA is predominantly located in dense sucrose fractions (secretory granules), whereas CgA64 is located near the top of the gradient (soluble protein fraction). In vitro incubation of these fractions revealed that the conversion of CgA did not occur in intact granules. These results indicate that CgA64 is not present in intact granules suggesting that it is not a naturally occurring secretory product in parathyroid cells. |
| Databáze: | OpenAIRE |
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